Five ways to identify the advantages and disadvantages of a switch

With the gradual deepening of network application, the Telecom class switch, especially the three-layer switch, has become the focus of the market contention. However, in different functions, a wide range of switch equipment, users how to remove the fog, to find their own application characteristics of the product? This not only requires users to start from the traditional switch evaluation indicators, consider the price of products, but also pay special attention to whether the product can provide some of the latest features with high value-added support.

Generally speaking, the evaluation of the advantages and disadvantages of the switch from the overall structure, performance and function of the three aspects. The overall architecture refers to the port density of the switch device, the maximum speed of the port support, the value of the exchange capacity and other basic performance parameters, so that the user can grasp the positioning and grade of the equipment in general.

In addition to the performance of the switch to meet the RFC2544 recommended basic standards, that is, throughput, delay, packet loss rate, with the increase in user business and application of in-depth, but also added some additional indicators, such as the number of MAC address, routing table capacity (three-tier switch), ACL number, LSP capacity, the number of support VPN. Take the number of MAC addresses as an example. The number of MAC addresses refers to the number of MAC addresses that can be stored in the MAC Address table of the switch, and the more MAC addresses are supported, the higher the rate of data forwarding.

function is the most direct indicator

For a general access layer switch, simple QoS guarantees, security mechanisms, support network management policies, spanning tree protocols, and VLANs are essential functions, but if carefully analyzed, some features can be further subdivided under simple representations, which are the main causes of product differences, It is also an important way to embody the value-added of products.

Application-Level QoS Assurance

In order to provide more flexibility for users in practical applications, the QoS policy of the switch must support the multi-level packet priority setting, which can be prioritized for MAC address, VLAN, IP address and port respectively. At the same time, the switch also has the ability of good congestion control and traffic limit, support DiffServ differentiated service, can distinguish different application flow according to source/Aim MAC/IP intelligence, meet the demand of real-time multimedia application. At present, some of the switches in the market, although also known as a QoS guarantee, but in fact only support the single level of priority settings, for the user's actual application to bring a lot of inconvenience.

VLAN support

VLAN namely virtual local area network, by dividing the LAN into VLAN segment of virtual network, can strengthen network management and network security, control unnecessary data broadcast, the Working Group of network can break through the geographical limit of the shared network, and divide the subnet according to the management function. Different vendor switches have different support capabilities for VLANs, and the number of VLAN support is different.

Network management function

The management software can be used to manage and configure the switches through the webmaster functions, such as through web browsers, Telnet, SNMP, Rmon, etc. Typically, switch vendors provide management software or a third-party management software remote Management switch. The general switch satisfies the SNMPMIBI/MIBII statistic management function, and supports the configuration management, the service quality management, the alert management and so on strategy, but the complex gigabit switch can support the RMON active monitoring function by adding the built-in RMON group (Mini-rmon). The strategy is supported by the ISCOM2826 switch, which can be managed by the integrated network management platform Rcnview of the company in SNMP.

Link Aggregation

Link aggregation makes the link bandwidth between switches and between switches and servers very scalable, such as Binding 2, 3, and 4 gigabit links, which multiplies the bandwidth of the link in a single way. The link aggregation technology can realize the load balance of different ports, and also can backup each other to ensure the redundancy of the link. In some gigabit Ethernet switches, up to 4 sets of link aggregations can be supported, with a maximum of 4 ports per group. Both spanning tree protocol and link aggregation can guarantee the redundancy of a network. Set up redundant links in one network and block the backup link with a spanning tree protocol, which logically does not form a loop and, in the event of a failure, enables the backup link. Our recommended three switch devices are effectively supported by link aggregation, spanning Tree protocol, where the GreenNet company's TiNetS3526 not only supports 8 10/100base-t adaptive ports, but also supports gigabit-port aggregation.

Support VRRP Protocol

VRRP (Virtual Routing Redundancy Protocol) is a solution to ensure network reliability. In this protocol, a redundant backup of the default gateway (DefaultGateway) of the terminal IP device on the shared multiple access media is performed, so that when one of the three-tier switch devices is down, the backup device will take over the forwarding work in time, providing transparent switching to the user and improving the quality of the network service. The VRRP protocol is similar to Cisco's HSRP protocol, except that HSRP is privately owned by Cisco. At present, the mainstream switch vendors have already supported the VRRP protocol in their products, but it still takes some time to apply it widely.